In recent years, fuel saving characteristics of vehicles are again regarded as important, as the global environmental issues are drawing more attention. As for the global environmental issues, measures need to be promptly taken against global warming. Thus, improvements to enhance fuel-saving performance have repeatedly been made for vehicles with engines that emit greenhouse gases such as carbon dioxide to reduce emissions of greenhouse gases through improvement of fuel efficiency.
However, no matter how high the original fuel saving characteristics of the vehicle are, if a driver's driving manner is against fuel saving, for example, if the vehicle is driven with an inappropriate selection position of the shift lever, driving of the vehicle is controlled with a shift not suited to road conditions and so wasteful fuel consumption is caused, making high fuel saving characteristics of the vehicle meaningless. Thus, there have been various conventional techniques for notifying the driver of an inappropriate shift lever position when the driver selects such an inappropriate shift lever position for driving so as to make a contribution to fuel-saving with the shift lever selection, even if the contribution is so small.
According to a conventional technique, for example, an excessive driving force generated when the shift change to a higher gear is possible is calculated by, calculating a difference between the current fuel consumption and a fuel consumption expected to be achieved when a higher gear is selected (this difference is referred to as “excessive fuel consumption caused by the omission of shift-up”), and converting the excessive fuel consumption to the driving force to obtain driving-force equivalent. Based on the excessive fuel consumption and the driving-force equivalent, it is possible to present to the driver how much fuel and driving force are wasted when an inappropriate shift lever position is selected during driving, for example, when second gear is selected though higher gear can be selected.